Baler

ABSTRACT

A baler having an improved hydraulically driven toggle mechanism for operating a baler pressing platen, improved bale ejector, and improved baler door latch. The toggle mechanism includes opposed pairs of first and second arms, each first arm of which is a generally C-shaped bell crank arm. The first arms are connected to provide a pressing mechanism which is compact but nonetheless has a long pressing stroke to facilitate production of a large bale in only a few pressing strokes. The bale ejector comprises a lifting plate having a hook which when engaged by a finger secured to the platen lifts the underside of a bale from the rear of the box as the platen is raised to cant the bale onto its forward edge permitting its easy removal from the baler. The lifting plate hook travels in a slot in the baler rear wall and is disengaged from the platen finger by a stop across the slot to drop the lifting plate to the bottom of the box in position for commencement of pressing of a new bale. And, the door latch comprises a rotatable pin and pivotal catch having arced and arcuate surfaces respectively which roll against each other during opening of the door latch to provide an easy opening door latch even when under heavy pressure from a compressed bale.

United States Patent 1 1 1 1 3,728,959

Fredrickson [451 Apr. 24, 1973 [54] BALER [57] ABSTRACT [76] Inventor:Wallace F. Fredrickson, 5224 Penn. A baler having an improvedhydraulically driven tog- I Avenue N., Minneapolis, Minn. gle mechanismfor operating a baler pressing platen,

- Y a 55428 v improved bale ejector, and improved baler door latch.

[22] Filed: Oct. 27 1970 The toggle mechanism includes opposed pairs offirst and second arms, each first arm of which is a generally [2]] Appl.No.: 84,371 C.-shaped bell crank arm. The first arms are connected toprovide a pressing mechanism which is compact but [52 us. c1. ..100/218,100/3, 100/100, nameless has a long smke facilitate 100 /2 45, loo/255,100 R72, 100 /286 production of a large bale m only a few pressing 51Int. Cl. ..B30b 15/32 stwkes- The bale eject comprises a fling Plate[58] Field of Search ..292/254, 25, DIG. 18; mg a which when engaged bya finger secured l 8 the platen t11 underside Of a bale from the rear Ofthe box as the platen is raised to cant the bale onto its forward edgepermitting its easy removal from the [56] References Cited baler. Thelifting plate hook travels in a slot in the baler rear wall and 1sdisengaged from the platen UNITED STATES PATENTS finger by a stop acrossthe slot to drop the lifting plate to the bottom of the box in positionfor commence- 2,243,205 5/1941 Hall ..l00/272 X ment of p g of a newbale. And the door latch 1,040,396 10/1912 Paalm. ..l0O/2l8 R9 89710,188] Riesel "loo/218 comprises a rotatable pm and pivotal catchhaving 3,280,727 10/1966 Jonas ..100/245 x awed and afcuate Surfacesrespectively which r011 l,i26,073 l/l9l5 Peterson et a1. ..l00/2l8 X g nt h Other during opening of the door latch to 3,195,447 7/1965 Taylor...l0O/2l8 X provide an easy opening door latch even when under1,856,531 5/1932 Berg 100/255 X heavy pressure from a compressed ba]e3,469,530 9/1969 Walker et al. 100/218 X 18 Claims, 5 Drawing FiguresPrimary Examiner-Billy .l. Wilhite Attorneyl(eith B. Davis BALERBACKGROUND AND FIELD OF THE INVENTION The present invention relates ingeneral to anti-pollution devices and in particular to refuse balers.

Air pollution has long been a problem. In large cities in particular theproblem is especially acute. It is recognized that many deaths of theelderly and of those afflicted with respiratory diseases areattributable to air pollution. It has been noted that the deathincidence of such people is markedly higher during high-pollutionperiods.

One source of air pollution is discharge from incinerators in whichrefuse, particularly paper and cardboard, is burned. Enormous quantitiesof shipping containers, alone, are disposed of daily by businesses ofall types. Many food stores, for example, have long disposed of thecardboard boxes in which their canned and dry goods are delivered byburning them in incinerators.

Incineration as a form of disposal is objectionable on the furtherground that it precludes recycling the material incinerated and is thuswasteful of natural resources. In the case of paper products disposed ofby burning, new timber must be cut to product papers that couldotherwise have come from the burned paper. An exploding population whoseconsumption per capita of combustible materials continues to rise,places an ever increasing demand on our natural resources.

An alternative to incineration which is nonpolluting and which permitsrecycling is baling. Devices which compact refuse such as paper andcardboard into a bale and secure the bale with some form of tie such aswire have long been known.

According to my invention I provide a baler which makes it economicallypractical to dispose of refuse by baling. I provide a baler which isinexpensive to construct and operate. It can be lightweight and smallenough to be easily portable while nonetheless providing a largepressing force throughout a long pressing stroke to produce large,compact bales. My baler, besides being easy to operate, incorporatesother labor and operating cost saving features including a speciallydesigned, long-wearing door latch which operates with a minimum offriction to have a long life and require a minimum of maintenance.Another labor saving feature is a bale ejection mechanism whichfacilitates easy and quick removal of a completed bale.

BRIEF DESCRIPTION OF INVENTION A baler having an improved hydraulicallydriven toggle mechanism for operating a baler pressing platen, improvedbale ejector, and improved baler door latch. The toggle mechanismincludes opposed pairs of first and second arms, each first arm of whichis a generally C-shaped bell crank arm. The first arms are connected toprovide a pressing mechanism which is compact but nonetheless has a longpressingv stroke to facilitate production of a large bale in only a fewpressing strokes. The bale ejector comprises a lifting plate having ahook which when engaged by a finger secured to the platen lifts theunderside of a bale from the rear of the box as the platen is raised tocant the bale onto its formed edge permitting its easy removal from thebaler. The lifting plate hook travels in a slot in the baler rear walland is disengaged from the platen finger by a stop across the slot todrop the lifting plate to the bottom of the box in position forcommencement of pressing of a new bale. Also, a part of my invention isa baler door latch which includes a rotatably mounted pin and apivotally mounted catch for engaging the pin. The catch includes aconcave arcuate surface which partially encircles and contacts an arcedsurface of the pin to latch the pin and catch. The pin also includes aprojection which contacts the catch as the pin is rotated during openingof the door. As the pin is rotated, the pin arced surface rolls on thecatch arcuate surface free or nearly free of sliding friction and theprojection contacts the catch to pivot the catch out of engagement withthe pin and unlatch the door.

BRIEF DESCRIPTION OF FIGURES Having thus briefly described my invention,I will now describe how to make and use a preferred embodiment of theinvention with reference to the accompanying drawings, wherein:

FIG. 1 is a front perspective view of a baler according to my invention;

FIG. 2 is a sectional view taken along line 22 of FIG. 1 illustratingthe baler door latch;

FIG. 2A illustrates a door latch according to FIG. 2 but with thepositions of the latch pin and catch reversed;

FIG. 3 is a front plan view of a first and of a second arm of the balerpressing mechanism shown in FIG. 1; and

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1 illustratingthe baler bale ejection mechanism and interconnection of the variouscomponents of the baler pressing mechanism.

DETAILED DESCRIPTION Referring now to FIG. 1, a baler according to myinvention is shown as 10. The baler is shown to comprise a pressing box12 in which a pressing platen 14 is disposed for reciprocable movementalong the vertical axis of the box. The box 12 has a pair of side walls16 and 18, a rear wall 20, a bottom 22 and a charging door 24 and lowerdoor 26. The box 12 tapers from front to back by having the rear wall 20narrower than doors 24 and 26. The bottom 22 is provided with a pair ofgrooves 28 and rear wall 20 includes a pair of corresponding slots 30,one of which is hidden from view by side wall 18. Rear wall 20 ispartially cut away to show a curved guideway 32 which runs from thebottom to the top of the lefthand slot 30; there is a similar guidewayfor the righthand slot. The grooves 28, slots 30, guideways 32, andgrooves 34 (in the underside of platen 14) cooperate to facilitatesecuring ties around a completed bale held in a compressed state byplaten l4. Platen 14 is provided on each side with a verticalcombination of rollers, the lefthand combination of which is shown as36. A similar combination of rollers is mounted in a like fashion to theright hand side of the platen but is hidden from view by side wall 18.Either the diameter of each of the rollers varies across the rollerwidth at a rate corresponding to the taper of the wall against which itrolls, or the axis of rotation of the rollers are set parallel to thewall against which they roll. The features described thus far are notconsidered a part of the present invention.

What is considered to be my present invention, still referring to FIG.1, are the door latch, bale ejection mechanism, and bale pressingmechanism shown generally as 38, 40, and 42, respectively. Three doorlatches are shown, they comprising a single elongate rotatably mountedpin 44 common to all three latches and three identical pivotably mountedcatches 54. Throughout this detailed description it is to be understoodthat where specific dimensions, angles, shapes, or the like are recited,they are not given by way of limitation but instead are given tofacilitate making and using a preferred embodiment of my invention andto illustrate the principles underlying my invention in general. Forexample, pin 44 in the preferred embodiment shown in FIG. 1 is a inchdiameter steel rod. However, it will be readily appreciated by one ofordinary skill in the art upon a reading of the following description ofthe door latch that pin 44 need not have a circular cross-section, butrather, need only have an arced surface in its circumference for rollingengagement with the catch.

Pin 44 is mounted for rotation to side wall 18 by mounting sockets, oneof which sockets is designated 46. Pin 44 rests on a pad 50 which iswelded to side wall 18. Also included in each door latch is a catch 54.Each catch is pivotably mounted by pivot 58 to a bracket 56 which inturn is secured to door 26. Bracket 56 is drilled and tapped forinsertion of pivot 58 which is a inch machine bolt; the bolt is screwedinto the bracket and locked .with a lock washer and nut. The center ofthe hole in bracket 56 for pivot 58 is about 1 inch outside the centerof pin 44.

Further details of a door latch are evident from Flg. 2 wherein anengagedcatch and pin as viewed along line 22 of FIG. 1 is shown. A viewof the catch pivoted to a disengaged position is shown in dashed lines.Pin 44 is shown to be also provided with a projection 48 and to beconnected to one end of a spring 68 which is connected at its other endto wall 18. Spring 68 acts as a pin positioning means in cooperationwith the pin handle 67 and the side wall reinforcement tube 69. Spring68 biases pin 44 in a latching position, and, although the springalonecould position the pin in latching position, the bend of handle 67 ismade to even more precisely position the pin projection 48 just out ofcontact with the catch 54 when the pin and catch are engaged.

Turning now to consideration of catch 54, it is seen in FIG. 2 to havean indentation in its side which faces toward pin 44. The catch 54 isfabricated from a blank which is a inch long piece of A inch mild-steelplate. The catch indentation includes a concave arcuate surface 60 whichfaces toward the catch pivot to partially encircle and contact the arcedsurface of pin 44. Surface 60 has the radius of a A inch diameter hole;this hole and the inch diameter pivot hole are spaced about 2% inchescenter to center. The center of the concave surface radius and the inchhole center are 3/16 and )4 inch from the side of the blank towards thepin. The foregoing dimensions and relationships insure positiveengagement of the pin and catch. To further protect against the catchsliding off and disengaging from the pin, the catch pivot point isplaced about one inch outside the pin center so that the catch anglesback towards the pin. During opening of the latch, as

pin 44 is rotated in a clockwise direction, the arced circumference ofthe pin rolls on the catch arcuate surface free or nearly free ofsliding friction as the projection strikes against the catch strikesurface 61 to pivot the catch out of engagement with the pin and unlatchthe door. Also included in the catch is a spring 64 which biases thecatch towards a closed position. The spring 64 is held in a hole drilledabout inch deep into bracket 56 by an L-shaped strip 66 secured to catch54. In FIG. 2, catch 54 and bracket 56 are partially cut away to showthe spring. Strip 66 in cooperation with a side and an end edge ofbracket 56 limits pivoting of catch 54 to between, respectively, oneposition away from the pin slightly more than necessary to disengage thecatch and pin and another position towards the pin slightly past theposition at which the pin and catch are engaged. These positions are notcritical, but are only selected to provide a freely operating door latchwhile avoiding excessive catch movement. With the door latch closed,spring 64 is under slight compression. As the catch is pivoted duringopening or closing, spring 64 becomes progressively more compressed toprovide a force for returning the catch to a closed position when thedoor reaches either an open or a closed position. Catch 54 is alsoprovided with a beveled end formed by surface 62 which is a continuationof the arcuate surface and which angles away from both the side of thecatch including the indentation and the catch pivot. During latching,the beveled end slidably contacts the pin to pivot the catch from theclosed position towards the open position until the beveled end slidesby and the indentation reaches the pin whereupon the spring 64 returnsthe catch to a closed position. In view 2A of FIG. 2 the pin 44 andcatch 54 are shown in their alternate position; namely, with pin 44mounted by mounting socket 46 to door 26 and catch 54 mounted by bracket56 to side wall 18.

Returning now to FIG. 1, the baler pressing mechanism 42 shall now bedescribed. The force producing means of the pressing mechanism comprisesa hydraulic system which includes a hydraulic cylinder 70 and piston 72which telescope in a conventional manner to produce a force in adirection always normal to the box vertical axis and along the twoopposite directions of the piston travel. For the preferred embodimentshown, a 4 inch diameter cylinder with a 10 inch stroke which produces aforce of 25,000 pounds is employed.

The remainder of the hydraulic system includes pumps, hoses connectingthe pumps to the cylinder, and switches for controlling the fluid flowbetween the pumps and cylinder. These latter components of the systemare mounted on the exterior of the box and may be constructed ofcommercially available, standard components in a well known manner.These components and their connection are incidental to the presentinvention.

A force translation means which converts at least a portion of a forceproduced by the hydraulic system to a re-directed force in a directionalong the box vertical axis includes front and rear sets of opposed armscomprising a front pair of opposed first arms, and 82, a rear pair ofopposed first arms, 84 and 86, a front pair of opposed second arms, 88and 90, and a rear pair of second arms, 92 and 94. These arms 80-94 areall of equal length; their construction shall be described later. Thefirst arms 80-86 are each a bell crank arm and are each rotatablysecured to one or the other of support members 96 and 98 which in turnare secured to the side walls of the pressing box. Support members 96and 98 are formed of 2 by 3 inch rectangular box tubing. The other endof each first arm is rotatably secured to an end of a second arm withopposing first arms being connected to different ones of a pair ofopposing second arms. The other end of each second arm is rotatablysecured to a leg of the pressing platen. The forward ones of these legsare visible in FIG. 1 and are designated as 100. All the axes aboutwhich the first and second arms 8094 rotate are parallel to each otherbut normal to the box vertical axis. The legs 100 are secured to thechannel irons which form the pressing platen and to front and rearreinforcement members 102 and 1104 which span the width of the platen.The hydraulic system force producing means is coupled to the forcetranslation means by a pair of cross-members each of which is pivotallyconnected between corresponding (front and rear) first arms. The piston72 is shown connected to one of the cross-members, designated 106.midway between the crossmember ends. The force translation meansprovides a large mechanical advantage to in turn permit use of a lowpressure and thus inexpensive hydraulic system. The force translationmeans also permits of a wide and deep pressing box in addition toproviding a long pressing stroke even through it also provides a highlycompact pressing mechanism when the pressing platen is fully withdrawn.The result is a large charging area which produces further economies asa large quantity of refuse can be loaded into the pressing box toproduce a large bale in only a few pressing strokes. The compactness ofthe pressing mechanism is due in part to the bends in the first andsecond arms, particularly those of the first arms. Although the bend ineach second arm may also contribute to a compact pressing mechanism, forreasons which will be explained later, for the embodiment shown, it ispossibleto achieve the same compactness with straight second arms. InFIG. 1, the end of arm 90 is partially cut away to illustrate that theend of arm 80 connected to the second arm is bent, as are all similarfirst arm ends; the cut away view makes it apparent that the first armsare folded between side pieces of the second arms as the arms approach aposition parallel to the box vertical axis. For the embodiment shown,the degree of parallelity achieved is dependent upon the construction ofthe first arm in a manner to be described in greater detail hereinafter.

The shapes of a first and a second arm of the illustrated preferredembodiment of FIG. 1 are more clearly shown in FIG. 3 wherein a firstand a second arm are shown drawn to scale. A first arm 150 is shown tohave a first straight segment thereof, designated as dimension F,extending between the end for connection with a side wall of the balerand the point for connection with a cross-member. The other end segmentis also straight and is dimensioned as G. Both segments F and G formangles, 25 and 15 degrees respectively, with the middle segment, whichmiddle segment is likewise straight and is dimensioned E in FIG. 3. The

end segments are approximately one-third and onetwelfth the length ofthe middle segment. The shorter segment and the bend angles are chosento minimize the pressing mechanism heighth yet provide a lever arm, C,which will start the platen moving downward readily with the platen in afully withdrawn position. The second arm 152 comprises only two segmentswhich form a bend of about 58 degrees. The length of the shorter segmentand the bend angle are chosen relative to the platen leg heighth so thatdimension B is as long as possible while dimension A approaches theheighth of platen leg 100. The first arm 150 is thus seen to have agenerally C-shape and the second arm a generally L-shape. As shown inFIG. 1, the C-shapes face each other and conversely the L-shapes faceaway from each other when the platen is in an extended position. Each ofthe bends serves to improve the baler pressing mechanism heighth tostroke ratio. In the preferred embodiment of FIG. 1, for a box width of36 inches, by utilizing curved arms having dimension as given below, aplaten stroke of 40 inches for a linkage mechanism heighth of only 12inches is provided. By contrast, the stroke and heighth for a mechanismwith straight arms having lenghths equal to dimensions B and D would be30 and 22 inches respectively.

arm 150 arm 15 2 C 2% in. A 4% in. D 24% B 24% in. E 18 in. H 6 in. F 6%R 58 G 1 /2 in. S l5 T 25 Because the first arms fold between the sidepieces of the second arms, Dimension H should be as small as possible;the shorter this dimension, the closer the second arm approaches tonormal to the box vertical axis when the platen is fully withdrawn. Ihave found that this H dimension can be reduced to 4 inches if thesecond arm 152 is straight instead of bent. However, no overall heightheduction is realized as the additional amount which the first arm foldsinto the second arm is offset since the reinforcement members 102 and104 are not brought above any part of the second arm. Nonetheless, someadvantages are realized as when straight arms are used it is not longernecessary to cut away any of the vertical edges of the channel irons ofplaten 14.

The construction and interconnection of a first and second arm and theirconnection with the pressing box 12, platen 14, and cross-member 106 areshown in FIG. 4, a sectional view taken through the middle of rear wall20 looking along line 44 of FIG. 1. As shown, the first arm 84 is ofsingle piece construction and is connected to spacer pad 132 and supportmember 98 by a pin 134. First arm 84 is also connected to cross member106 by a pin 108. Second arm 94 is of multipiece construction,consisting of a pair of identical side pieces 136 and 138 which sandwichan end of the first arm 84 and a connecting member 140. A pin 133connects first arm 84 and second arm 94, while the second arm isconnected by its connecting member 140 with a pin 134 to leg 100 andreinforcement member 104. Although they have been omitted for the sakeof clarity, it will be appreciated that each bearing surface of pins108, 133, and 134 is supplied with a lubricant through grease fittings.An anti-seize and lubricating compound such as that sold under the TradeName of Never-Seez by the Never-Seez Corporation of Broadview Illinoishas been found to be an acceptable lubricant.

Returning again to FIG. 1, the bale ejection mechanism 40 shall now bedescribed. It is shown to include a lifting plate 1 which normally restsflat on the bottom of the baler next to the rear wall. The depth of theplate 110 is important and should be about /Bth the box depth. It hasbeen found that when this dimension is increased to about l/6th the boxdepth the plate tends to lift the entire bale instead of canting thebale onto its forward edge. Lifting plate 1 10 is secured by a spacer111 to a bar 112. Spacer 111 is slightly thicker than the thickness ofrear wall to permit free vertical movement of plate 110 as well as aslight pivoting of bar 112 in a manner as will be explained later. Theupper end of bar 112 terminates in a hook 114 which extends through aslot 1 16 in the baler rear wall and has a lower surface 117 and anupper surface 118 each of which slope from the rear wall towards thebottom of the box. The bar 112 is similarly sloped for about onehalf onits width. A slot 120 in rear wall 20 permits vertical movement of plate110. The remainder of the ejection mechanism includes a finger 122secured to platen 14 and movable by a handle 124 into position forengagement by hook 114. Finger 122 and handle 124 are mounted to platen14 by pipe 126 and are offangle so that there are as a practical matteronly two stable positions for the finger, one being an upright neutralposition as shown in FIG. 1 with the handle resting on the uprightflange of the platen and the other being an engagement position withfinger 122 lying horizontally on the platen. A stop 128 having the sameslope as surface 118 is affixed across slot 116 at the point at whichthe hook and finger are to be disengaged.

The manner in which the bale ejection mechanism operates and furtherdetails of its construction shall now be described with reference toFIG. 4. It will be appreciated that during compensation of a bale,finger 122 is in the neutral position to permit platen 14 to descendbelow hook 114 by virtue of a cut-out in the platen which is wide enoughto permit passage by hook 114 but narrow enough that finger 122 bridgesthe cutout when in the engagement position. The far surface of thecut-out is shown in FIG. 4 as 121. With finger 122 in position forengagement, hook 114 is engaged by the finger as platen 14 is raised toin turn lift plate 110. Lifting of plate 110 continues until surface 118slidably contacts stop 128 whereupon hook 114 is forced out of the slotto disengage the hook from the finger and drop the lifting plate to thebottom of the baler. As plate 110 drops, a wedge shaped projection 129on bar 112 slides against a U-shaped strap 130 to force hook 114 intothe box. During the next downward stroke of platen 14, finger 122 isstill in the engagement position. As platen 14 moves downward past hook114, finger 122 upon striking the upper surface 118 of the hook isrotated towards its neutral position. Because of the angle betweenhandle 124 and finger 122, a finger 122 is rotated towards its neutralposition, the center of gravity of the finger, handle and theirconnecting piece passes to the right of center whereupon the handleflips over against the platen to return the finger to its neutralposition.

As is apparent in FIG. 4, the under surface 117 of hook. 114 whichcontacts finger 122 slopes gradually from the rear wall downwardstowards the bottom of the box. It has been found that without thisslope, the hook tends to disengage prematurely. A slope for surface 117of about 8 has been found acceptable when used with a surface 118 havinga slope of about 60. If this latter angle becomes appreciably less than60, such as about 50, I have found that there is excessive frictionbetween the stop 128 and hook surface 118. Returning to the descriptionof lifting plate 110, it is shown to be joined by a spacer 111 to bar 112. For the embodiment shown, side and rear walls 16, 18 and 20 are 3/16inch sheet steel. Spacer 111 is A inch thick; this thickness has beenfound sufficiently wide to permit pivoting of bar 1 12 as hook l 14 isforced out of slot 116.

In a version of the foregoing described preferred embodiment used forcompressing corrugated cardboard, the following was found suitable forproducing bales weighing in excess of 150 pounds:

side walls 16 & 18 3/16 inch sheet steel,

80 inches high by 24 inches deep;

rear wall 20 3/16 inch sheet steel,

80 inches high by 36 inches wide;

pin 44 inch dia. hot rolled steel rod by 1% inch bar stock with a inchdia. hole for accepting pin 44; 2% inch long piece of V: by inch coldrolled bar stock;

mounting socket 46 projection 48 1% by Ii: in. angle iron;

an Energy Manufacturing Inc. CTR series 4 in. dia. and 10 in. stroke,Monticello, Iowa;

hydraulics & 72)

first arms -86 supports 96 & 98

leg 100 members 102 & 104

cross-mernber 106 pin 108 plate 1 10 bar 112 hook 114 slot 116 slot 120finger 122 stop 128 and wedge 129 strap 130 spacer 132 pin 133 pin 134side pieces 136 & 138 connector 140 l in. plate steel;

7 gauge, 2 by 3 in. box tubing;

5 in. piece of by 2% in. bar stock;

7 gauge, 1% by 3 in.

box tubing;

1% by 3 in. bar stock;

5 in. length of 1% in.

dia. cold rolled rod;

13 in. piece of3 by 3 by 3/16 in. angle iron;

34 in. piece of W: by

32 bar stock;

cut from by 2 in.

bar stock;

% in. wide by 11 in. long; one in. wide by 15 in. long; 56 in. dia. hotrolled steel rod;

l by 2 by /4 in. angle iron; A by 1% bar stock 3 in. piece of by 2% in.bar stock 1 in. dia. cold rolled steel rod;

1% in. dia. stress proof pin;

% by 2% in. bar stock 1 by 3 in. bar stock Having thus described apreferred embodiment of my invention, it will be readily apparent thatnumerous variations and modifications thereof are possible. For example,the hydraulic cylinder and piston are shown connected to the first armsto form a second class lever; connections which form first and thirdclass levers are of course possible. Likewise, it would be possible toconnect the force producing means between the second arms to form first,second, or third class levers.

Although my invention has been shown as having four first and foursecond arms connected as two sets of arms on each side of the box, asingle set of arms on each side, preferably centered between the frontand b ack of the platen, would suffice. Similarly within my invention isa baler having two additional sets of arms on each side of the pistonand cylinder connected in tandem with the existing arms to cross-membersconnected to extensions of the piston and cylinder and to extensions ofsupport members 96 and 98; such an arrangement would facilitateconstruction of a wider baler.

While the invention has been described with reference to a preferredembodiment, it is to be understood that the above modifications andvariations and others not specifically mentioned are within the spiritand scope of the invention.

What is claimed is:

l. A baler comprising a pressing box having a rear wall, a pair of sidewalls, a door hinged to a side wall; a platen mounted for reciprocablemovement within the pressing box; and a door latch which includes arotatably mounted pin and a pivotally mounted catch for engaging thepin, either the pin or the catch being mounted to the baler door and theother being mounted to a side wall of the baler, the side of the catchwhich faces the pin when the door is closed having an indentation forpartially encircling and engaging the pin, the indentation including aconcave arcuate surface which faces toward the catch pivot and the pinhaving an arced surface in its circumference on a radius of the pin axisof rotation, which arced surface faces away from the catch pivot whenthe catch and pin are in position for engagement, the concave arcuatesurface having a radius greater than the arced surface radius andpartially encircling and contacting the arced surface when the pin andcatch are engaged, and which pin includes a projection for contactingthe catch as the pin is rotated in a direction to pivot the catch out ofengagement with the pin during opening of the door, as the catch pivotsthe pin arced surface rolls on the catch arcuate surface to pivot thecatch and unlatch the door.

2. A baler according to claim 1 wherein the pin is of circular crosssection and wherein the arcuate surface has a length greater than thepin radius to accept more than one-half of the pin in the indentationwhen the pin and catch are engaged.

3. A baler according to claim 2 wherein the catch further comprisesmeans for limiting pivoting of the catch to between an open positionaway from the pin slightly further than necessary to disengage the pinand catch and a closed position towards the pin and just past theposition at which the pin and catch are engaged.

4. A baler according to claim 3 wherein the catch further comprisescatch positioning means which biases the catch towards the closedposition.

5. A baler according to claim 4 wherein the catch has a beveled endformed by a surface which is a continuation of the arcuate surface andwhich angles away from both the side of the catch including theindentation and the catch pivot, which beveled end slidably contacts thepin as the door is being closed to pivot the catch from the closedposition towards the open position until the beveled end slides by andthe indentation reaches the pin whereupon the catch positioning meansreturns the catch to a closed position with the arcuate surfacepartially encircling and contacting the pin.

6. A baler according to claim 5 wherein the pin further comprises pinpositioning means which biases the pin in a latching position at whichthe projection will contact the catch upon slight rotation of the pin ina direction to disengage the pin and catch.

7. A baler according to claim 6 wherein the pin positioning meanscomprises a spring coupled to the baler and to the pin to exert atorsional force against the pin as the pin is rotated from the latchingposition.

8. A baler according to claim 7 wherein the catch positioning meanscomprises a coil spring held between the baler and the catch, the springacting against the catch during opening and closing of the door latchand the spring returning the catch to a closed position when the door isin either an open or a closed position.

9. A baler according to claim 7 wherein the spring is in relatively lowcompression when the catch is in the closed position but which becomesincreasingly more compressed as the catch pivots during opening andclosing of the door.

10. A baler having a pressing box having a bottom, a rear wall, a pairof side walls, a platen, a door hinged to one side wall, and a doorlatch for latching the door to the other side wall and a bale ejectionmechanism which comprises:

in the rear wall, a first slot in and extending upwardly from the bottomof the wall and a second slot in vertical alignment with the first slotand extending upwardly from slightly above the top of a completed bale:

bale lifting means including an angle iron having one side whichnormally lies flat against the baler bottom and which is of a dimensionsufficient to provide canting of a bale upon raising the lifting meansand the other side of which angle iron normally abuts the baler rearwall; and

releasable bale lifting engagement means including a book which normallyis at the bottom of and extends through the second slot, which hook hasan upper surface and an under surface which both slope from the rearwall toward the bottom of the box, the upper surface sloping steeply atan angle of about 60 and the under surface sloping gradually at an angleof about 8, a bar connected to the hook and extending downwardly to thebottom of the baler in alignment with the first slot, a spacer of athickness slightly greater than the rear wall disposed in the first slotand connecting the bar and the angle iron, a finger on the platenmoveable into position for engagement by the hook when the platen isholding a completed bale in a compressed state, and a stop across thesecond slot at a heighth at which the hook is to be disengaged from thefinger.

11. A baler comprising a pressing box having a rear wall, a pair of sidewalls, a bottom, and a door hinged to one of the side walls;

a door latch including a rotatably mounted pin and a pivotably mountedcatch for engaging the pin, either the'pin or the catch being mounted tothe baler door and the other being mounted to a side wall of the baler,the side of the catch which faces the pin when the door is closed havingan indentation for partially encircling and engaging the pin, theindentation including a concave arcuate surface which faces toward thecatch pivot and the pin having an arced surface inits circumference on aradius of the pin axis of rotation, which arced surface faces away fromthe catch pivot when the catch and pin are in position for engagement,the concave arcuate surface having a radius greater than the arcedsurface radius and partially encircling and contacting the arced surfacewhen the pin and catch are engaged, and which pin includes a projectionfor contacting the catchas the pin is rotated in a direction to pivotthe catch out of engagement with the pin during opening of the door, asthe catch pivots the pin arced surface rolls on the catch arcuatesurfaceto pivot the catch and unlatch the door;

a pressing platen for reciprocable movement parallel to the box wallsbetween a withdrawn position near the top of the box and an extendedposition toward the bottom of the box;

a pressing mechanism comprising front and rear sets of opposed arms,each set of arms having a pair of facing, C-shaped first arms each ofwhich is rotatably connected at one end to a support 5 member near thetop of the box and rotatably connected at an opposite end to an end of asecond arm the opposite end of which is rotatably con nected to thepressing platen, a first cross-member connected between one pair offront and rear first 40 arms and another cross-member connected betweenthe other pair of front and rear first arms, the cross-member beingconnected equal distances from the ends of the first arms connected tothe support members and a hydraulic cylinder and piston having thepiston connected to one crossmember and the cylinder connected to theother cross-member; and

a bale ejection mechanism comprising a lifting plate which normallyrests flat on the bottom against the rear wall, a spacer connected tothe plate and disposed in a first vertical slot in the rear wall, a barconnected to the spacer and extending upwardly to the bottom of a secondvertical slot in the rear wall at a height slightly above the top of acompleted bale, a hook connected to the bar and extending through thewall and into the baler, the hook having an upper and an under surfaceboth of which slope from the rear wall toward the bottom, the uppersurface sloping steeply at'an angle of about 60 and the under surfacesloping gradually at an angle of about 8, a finger on the platen andmoveable from a neutral position into a position for engagement with theunder surface of the hook when the platen is holding a bale in acompressed state, and a stop across the second slot at a heighth atwhich the finger and hook are to bedisengaged.

12. A baler having a pressed box, a pressing platen and a pressingmechanism comprising a toggle mechanism for reciprocally moving thepressing platen between a withdrawn and an extended position and whichincludes at least a pair of opposing sets of arms, each set including agenerally C-shaped first arm and a second arm, each of which C-shapedfirst arms comprises a straight middle segment between a pair ofstraight end segments and is rotatably connected at one end to a sidewall of, and near the top of, the pressing box to face each other whenthe platen is in an extended position, which second arms are rotatablyconnected at one end to the pressing platen, and the other end of whichfirst and second arms are connected to each other, which first arms areequal length and which second arms are equal length, and all axes ofrotation of all first and second arms are parallel to each other butnormal to the box axis; and

a hydraulic system which includes a piston and a cylinder, which pistonand cylinder are connected between corresponding ends of a pair ofopposing arms whereby expansion and contraction of the hydraulic systemrotates the toggle mechanism first and second arms from a positionapproaching normal to the box axis to a position approaching parallel tothe box axis to provide a compact pressing mechanism and a largecharging area when the platen is in a withdrawn position, therebyfacilitating production of a large bale in only a few pressing strokes.

13. A baler according to claim 12 in which the baler pressing box has abottom and a rear wall and has a bale ejection mechanism including alifting plate which normally lies flat on the pressing box bottom nextto the rear wall, and an engagement means for releasably engaging thelifting plate with the pressing platen during an upward movement of theplaten, which engagement means comprises:

a hook secured to the lifting plate and extending through a verticalslot in the rear wall at a position above a completed bale, the hookhaving a beveled upper surface which slopes from the rear wall towardsthe bottom of the box;

a finger secured to the platen and adapted to be moved into position forengagement by the hook as the platen is raised from a completed bale;and

a stop across the slot at a position at which the hook is to bedisengaged from the finger, the platen when the hook and finger areengaged during an upward stroke of the pressing platen drawing thelifting plate upwardly until the beveled edge of the hook slidablycontacts the stop to force the hook out of the box and disengage thehook and finger to drop the lifting plate to the bottom of the box.

14. A baler according to claim 13 having a door hinged to one side ofthe pressing box which is closed and latched to confine and permitcompression of refuse in the baler but which is unlatched and opened topermit removal of a completed bale, further comprising a door latchwhich includes a rotatably mounted pin and a pivotably mounted catch forengaging the pin, either the pin or the catch being mounted to the balerdoor and the other being mounted to a side wall of the baler, the sideof the catch which faces the pin when the door is closed having anindentation for partially encircling and engaging the pin, theindentation including a concave arcuate surface which faces toward thecatch pivot and the pin having an arced surface in its circumference ona radius of the pin axis of rotation, which arced surfaced faces awayfrom the catch pivot when the catch and pin are in position forengagement, the concave arcuate surface having a radius greater than thearced surface radius and partially encircling and contacting the arcedsurface when the pin and catch are engaged, and which pin includes aprojection for contacting the catch as the pin is rotated in a directionto pivot the catch out of engagement with the pin during opening of thedoor, as the catch pivots the pin arced surface rolls on the catcharcuate surface to pivot the catch and unlatch the door.

15. A baler according to claim 12 wherein each segment of each generallyC-shaped first arm is connected to the pressing box at one end and theother of said end segments is connected to a said second arm, and saidfirst and other end segments are joined to the middle segment at anglesrespectively of 25 and 15 and have lengths respectively one-third andone-twelfth the middle segment length.

16. A baler according to claim 12 wherein:

each second arm is generally L-shaped and is connected to the platen bya leg on the platen, each second arm comprises a pair of straightsegments, a first segment of which has a length less than the length ofand is connected to the platen leg, and the L-shaped arms face away fromeach other when the platen is in an extended position.

17. A baler according to claim 16 wherein each said generally L-shapedarm comprises a pair of straight segments joined at an angle of about60.

18. A baler according to claim 16 wherein the toggle mechanism comprisestwo sets of opposing pairs of 'arms, one set connected towards the rearand the other connected towards the front of the pressing box andwherein the hydraulic system further comprises a crossmember pivotallyconnected between front and rear arms on one side of the box and anothercross-member connected between front and rear first arms on the otherside of box; the piston of said hydraulic system being connected to oneand the cylinder of said hydraulic system being connected to the otherof the cross members.

1. A baler comprising a pressing box having a rear wall, a pair of side walls, a door hinged to a side wall; a platen mounted for reciprocable movement within the pressing box; and a door latch which includes a rotatably mounted pin and a pivotably mounted catch for engaging the pin, either the pin or the catch being mounted to the baler door and the other being mounted to a side wall of the baler, the side of the catch which faces the pin when the door is closed having an indentation for partially encircling and engaging the pin, the indentation including a concave arcuate surface which faces toward the catch pivot and the pin having an arced surface in its circumference on a radius of the pin axis of rotation, which arced surface faces away from the catch pivot when the catch and pin are in position for engagement, the concave arcuate surface having a radius greater than the arced surface radius and partially encircling and contacting the arced surface when the pin and catch are engaged, and which pin includes a projection for contacting the catch as the pin is rotated in a direction to pivot the catch out of engagement with the pin during opening of the door, as the catch pivots the pin arced surface rolls on the catch arcuate surface to pivot the catch and unlatch the door.
 2. A baler according to claim 1 wherein the pin is of circular cross section and wherein the Arcuate surface has a length greater than the pin radius to accept more than one-half of the pin in the indentation when the pin and catch are engaged.
 3. A baler according to claim 2 wherein the catch further comprises means for limiting pivoting of the catch to between an open position away from the pin slightly further than necessary to disengage the pin and catch and a closed position towards the pin and just past the position at which the pin and catch are engaged.
 4. A baler according to claim 3 wherein the catch further comprises catch positioning means which biases the catch towards the closed position.
 5. A baler according to claim 4 wherein the catch has a beveled end formed by a surface which is a continuation of the arcuate surface and which angles away from both the side of the catch including the indentation and the catch pivot, which beveled end slidably contacts the pin as the door is being closed to pivot the catch from the closed position towards the open position until the beveled end slides by and the indentation reaches the pin whereupon the catch positioning means returns the catch to a closed position with the arcuate surface partially encircling and contacting the pin.
 6. A baler according to claim 5 wherein the pin further comprises pin positioning means which biases the pin in a latching position at which the projection will contact the catch upon slight rotation of the pin in a direction to disengage the pin and catch.
 7. A baler according to claim 6 wherein the pin positioning means comprises a spring coupled to the baler and to the pin to exert a torsional force against the pin as the pin is rotated from the latching position.
 8. A baler according to claim 7 wherein the catch positioning means comprises a coil spring held between the baler and the catch, the spring acting against the catch during opening and closing of the door latch and the spring returning the catch to a closed position when the door is in either an open or a closed position.
 9. A baler according to claim 7 wherein the spring is in relatively low compression when the catch is in the closed position but which becomes increasingly more compressed as the catch pivots during opening and closing of the door.
 10. A baler having a pressing box having a bottom, a rear wall, a pair of side walls, a platen, a door hinged to one side wall, and a door latch for latching the door to the other side wall and a bale ejection mechanism which comprises: in the rear wall, a first slot in and extending upwardly from the bottom of the wall and a second slot in vertical alignment with the first slot and extending upwardly from slightly above the top of a completed bale: bale lifting means including an angle iron having one side which normally lies flat against the baler bottom and which is of a dimension sufficient to provide canting of a bale upon raising the lifting means and the other side of which angle iron normally abuts the baler rear wall; and releasable bale lifting engagement means including a hook which normally is at the bottom of and extends through the second slot, which hook has an upper surface and an under surface which both slope from the rear wall toward the bottom of the box, the upper surface sloping steeply at an angle of about 60* and the under surface sloping gradually at an angle of about 8*, a bar connected to the hook and extending downwardly to the bottom of the baler in alignment with the first slot, a spacer of a thickness slightly greater than the rear wall disposed in the first slot and connecting the bar and the angle iron, a finger on the platen moveable into position for engagement by the hook when the platen is holding a completed bale in a compressed state, and a stop across the second slot at a heighth at which the hook is to be disengaged from the finger.
 11. A baler comprising a pressing box having a rear wall, a pair of side walls, a bottom, and a door hinged to one of the side walls; a door lAtch including a rotatably mounted pin and a pivotably mounted catch for engaging the pin, either the pin or the catch being mounted to the baler door and the other being mounted to a side wall of the baler, the side of the catch which faces the pin when the door is closed having an indentation for partially encircling and engaging the pin, the indentation including a concave arcuate surface which faces toward the catch pivot and the pin having an arced surface in its circumference on a radius of the pin axis of rotation, which arced surface faces away from the catch pivot when the catch and pin are in position for engagement, the concave arcuate surface having a radius greater than the arced surface radius and partially encircling and contacting the arced surface when the pin and catch are engaged, and which pin includes a projection for contacting the catch as the pin is rotated in a direction to pivot the catch out of engagement with the pin during opening of the door, as the catch pivots the pin arced surface rolls on the catch arcuate surface to pivot the catch and unlatch the door; a pressing platen for reciprocable movement parallel to the box walls between a withdrawn position near the top of the box and an extended position toward the bottom of the box; a pressing mechanism comprising front and rear sets of opposed arms, each set of arms having a pair of facing, C-shaped first arms each of which is rotatably connected at one end to a support member near the top of the box and rotatably connected at an opposite end to an end of a second arm the opposite end of which is rotatably connected to the pressing platen, a first cross-member connected between one pair of front and rear first arms and another cross-member connected between the other pair of front and rear first arms, the cross-member being connected equal distances from the ends of the first arms connected to the support members and a hydraulic cylinder and piston having the piston connected to one cross-member and the cylinder connected to the other cross-member; and a bale ejection mechanism comprising a lifting plate which normally rests flat on the bottom against the rear wall, a spacer connected to the plate and disposed in a first vertical slot in the rear wall, a bar connected to the spacer and extending upwardly to the bottom of a second vertical slot in the rear wall at a heighth slightly above the top of a completed bale, a hook connected to the bar and extending through the wall and into the baler, the hook having an upper and an under surface both of which slope from the rear wall toward the bottom, the upper surface sloping steeply at an angle of about 60* and the under surface sloping gradually at an angle of about 8*, a finger on the platen and moveable from a neutral position into a position for engagement with the under surface of the hook when the platen is holding a bale in a compressed state, and a stop across the second slot at a heighth at which the finger and hook are to be disengaged.
 12. A baler having a pressing box, a pressing platen and a pressing mechanism comprising a toggle mechanism for reciprocally moving the pressing platen between a withdrawn and an extended position and which includes at least a pair of opposing sets of arms, each set including a generally C-shaped first arm and a second arm, each of which C-shaped first arms comprises a straight middle segment between a pair of straight end segments and is rotatably connected at one end to a side wall of, and near the top of, the pressing box to face each other when the platen is in an extended position, which second arms are rotatably connected at one end to the pressing platen, and the other end of which first and second arms are connected to each other, which first arms are equal length and which second arms are equal length, and all axes of rotation of all first and second arms are parallel to each other but normal to the box axis; and a hydraulic system which includes a pIston and a cylinder, which piston and cylinder are connected between corresponding ends of a pair of opposing arms whereby expansion and contraction of the hydraulic system rotates the toggle mechanism first and second arms from a position approaching normal to the box axis to a position approaching parallel to the box axis to provide a compact pressing mechanism and a large charging area when the platen is in a withdrawn position, thereby facilitating production of a large bale in only a few pressing strokes.
 13. A baler according to claim 12 in which the baler pressing box has a bottom and a rear wall and has a bale ejection mechanism including a lifting plate which normally lies flat on the pressing box bottom next to the rear wall, and an engagement means for releasably engaging the lifting plate with the pressing platen during an upward movement of the platen, which engagement means comprises: a hook secured to the lifting plate and extending through a vertical slot in the rear wall at a position above a completed bale, the hook having a beveled upper surface which slopes from the rear wall towards the bottom of the box; a finger secured to the platen and adapted to be moved into position for engagement by the hook as the platen is raised from a completed bale; and a stop across the slot at a position at which the hook is to be disengaged from the finger, the platen when the hook and finger are engaged during an upward stroke of the pressing platen drawing the lifting plate upwardly until the beveled edge of the hook slidably contacts the stop to force the hook out of the box and disengage the hook and finger to drop the lifting plate to the bottom of the box.
 14. A baler according to claim 13 having a door hinged to one side of the pressing box which is closed and latched to confine and permit compression of refuse in the baler but which is unlatched and opened to permit removal of a completed bale, further comprising a door latch which includes a rotatably mounted pin and a pivotably mounted catch for engaging the pin, either the pin or the catch being mounted to the baler door and the other being mounted to a side wall of the baler, the side of the catch which faces the pin when the door is closed having an indentation for partially encircling and engaging the pin, the indentation including a concave arcuate surface which faces toward the catch pivot and the pin having an arced surface in its circumference on a radius of the pin axis of rotation, which arced surface faces away from the catch pivot when the catch and pin are in position for engagement, the concave arcuate surface having a radius greater than the arced surface radius and partially encircling and contacting the arced surface when the pin and catch are engaged, and which pin includes a projection for contacting the catch as the pin is rotated in a direction to pivot the catch out of engagement with the pin during opening of the door, as the catch pivots the pin arced surface rolls on the catch arcuate surface to pivot the catch and unlatch the door.
 15. A baler according to claim 12 wherein each segment of each generally C-shaped first arm is connected to the pressing box at one end and the other of said end segments is connected to a said second arm, and said first and other end segments are joined to the middle segment at angles respectively of 25* and 15* and have lengths respectively one-third and one-twelfth the middle segment length.
 16. A baler according to claim 12 wherein: each second arm is generally L-shaped and is connected to the platen by a leg on the platen, each second arm comprises a pair of straight segments, a first segment of which has a length less than the length of and is connected to the platen leg, and the L-shaped arms face away from each other when the platen is in an extended position.
 17. A baler according to claim 16 wherein each said generally L-shaped arm comprises a pair of straight segments joined at an anGle of about 60* .
 18. A baler according to claim 16 wherein the toggle mechanism comprises two sets of opposing pairs of arms, one set connected towards the rear and the other connected towards the front of the pressing box and wherein the hydraulic system further comprises a cross-member pivotally connected between front and rear arms on one side of the box and another cross-member connected between front and rear first arms on the other side of box; the piston of said hydraulic system being connected to one and the cylinder of said hydraulic system being connected to the other of the cross members. 